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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.myfaces.shared_orchestra.util;
20  
21  import java.util.HashMap;
22  import java.util.Map;
23  import java.util.Set;
24  import java.util.Iterator;
25  
26  
27  /**
28   * @author Anton Koinov (latest modification by $Author: grantsmith $)
29   * @version $Revision: 472630 $ $Date: 2006-11-08 15:40:03 -0500 (Wed, 08 Nov 2006) $
30   */
31  public class HashMapUtils
32  {
33      //~ Constructors -------------------------------------------------------------------------------
34  
35      protected HashMapUtils()
36      {
37          // block public access
38      }
39  
40      //~ Methods ------------------------------------------------------------------------------------
41  
42      /**
43       * Calculates initial capacity needed to hold <code>size</code> elements in
44       * a HashMap or Hashtable without forcing an expensive increase in internal
45       * capacity. Capacity is based on the default load factor of .75.
46       * <p>
47       * Usage: <code>Map map = new HashMap(HashMapUtils.calcCapacity(10));<code>
48       * </p>
49       * @param size the number of items that will be put into a HashMap
50       * @return initial capacity needed
51       */
52      public static final int calcCapacity(int size)
53      {
54          return ((size * 4) + 3) / 3;
55      }
56  
57      /**
58       * Creates a new <code>HashMap</code> that has all of the elements
59       * of <code>map1</code> and <code>map2</code> (on key collision, the latter
60       * override the former).
61       *
62       * @param map1 the fist hashmap to merge
63       * @param map2 the second hashmap to merge
64       * @return new hashmap
65       */
66      public static HashMap merge(Map map1, Map map2)
67      {
68          HashMap retval = new HashMap(calcCapacity(map1.size() + map2.size()));
69  
70          retval.putAll(map1);
71          retval.putAll(map2);
72  
73          return retval;
74      }
75  
76       /**
77       * spit out each name/value pair
78       */
79      public static String mapToString(Map map){
80          Set entries = map.entrySet();
81          Iterator iter = entries.iterator();
82          StringBuffer buff = new StringBuffer();
83          while (iter.hasNext())
84          {
85              Map.Entry entry = (Map.Entry) iter.next();
86              buff.append("[" + entry.getKey() + "," + entry.getValue() + "]\n");
87          }
88          return buff.toString();
89      }
90  
91  }